gm drum brake adjustment

GM Drum Brake Adjustment A Comprehensive Guide

Drum brakes have been a staple in automotive design for decades, particularly in older vehicles manufactured by General Motors (GM). While modern vehicles are increasingly equipped with disc brakes, understanding how to adjust GM drum brakes is essential for maintaining optimal brake performance and safety. This article will delve into the intricacies of adjusting GM drum brakes, offering step-by-step guidance for both the novice and experienced car enthusiast.

Understanding Drum Brakes

Drum brakes utilize a cylindrical drum that rotates with the wheel. Inside the drum are brake shoes, which are connected to the brake assembly. When the brake pedal is pressed, hydraulic pressure forces the shoes outward against the drum, creating friction that slows the vehicle down. Over time, the brake shoes wear down and the drum can become misaligned, leading to reduced braking efficiency. Regular adjustments are necessary to ensure optimal performance.

Tools Needed for Adjustment

Before beginning the adjustment process, it's crucial to gather the necessary tools

1. Jack and jack stands 2. Lug wrench 3. Screwdriver set (flathead and Phillips) 4. Brake adjustment tool (if needed) 5. Clean rags 6. Brake cleaner

1. Safety First Park your vehicle on a flat surface and set the parking brake. Loosen the lug nuts on the rear wheels slightly.

2. Elevate the Vehicle Use the jack to lift the rear of the vehicle and secure it with jack stands. Remove the wheel by fully loosening the lug nuts.

3. Exposing the Drum Once the wheel is off, you will see the drum brake assembly. Inspect the brake drum for any visible signs of wear or damage.

4. Cleaning Use brake cleaner to remove dust and debris from the drum and brake components. This ensures that your adjustments are made on a clean surface.

5. Adjusting the Brake Shoes Locate the adjustment mechanism. On most GM drum brakes, this is typically found at the bottom of the backing plate. Use a flathead screwdriver to turn the star wheel. Turning the wheel upward will expand the brake shoes, while turning it downward will retract them.

6. Check Shoe Position As you adjust, manually spin the drum to ensure that it rotates freely. You want the shoes to be just touching the inside of the drum; they should not be overly tight, which can lead to dragging brakes and premature wear.

7. Test the Adjustment After you have adjusted the shoes, repeat the process for the other side. Once finished, reinstall the wheel and lug nuts, hand-tightening them.

8. Lowering the Vehicle Carefully lower the vehicle back to the ground, and then fully tighten the lug nuts in a crisscross pattern to ensure even tightening.

9. Testing the Brakes Before driving, pump the brake pedal a few times to seat the brake shoes properly against the drum. Take the vehicle for a short test drive, paying attention to the brake performance. Listen for any unusual noises, which could indicate that further adjustment is necessary.

Tips for Effective Maintenance

- Regularly inspect your drum brakes for wear. This includes checking the thickness of the brake shoes and the condition of the drum. - Consider replacing the brake shoes if they are less than 1/8 inch thick. - Ensure that your brake lines are free from leaks and that the hydraulic system is functioning correctly.

Conclusion

Adjusting GM drum brakes is a vital skill for any car owner or enthusiast who wants to ensure their vehicle is safe and performs well. With the right tools and a bit of patience, this maintenance task can lead to better braking performance, extended lifespan of brake components, and peace of mind while driving. Regular checks and adjustments will not only enhance safety but also prevent more extensive and costly repairs in the future.